Access the Corporate Directory (Desk Phone)

From the physical desk phone, press the Home Button. This button has an image of a house & is most likely to the right of the directional buttons.
Press (4) Directories. Alternatively, use the arrow keys to scroll down to this option.
Press (2) Corporate Directory.
Use the number pad to type in the name of the person or department. Press Submit using the corelating button under the screen.
You should now be brought to a menu with the user(s) you've searched for.